System and method for cleaning external walls of building

Abstract

This solution is for washing and cleaning the external walls of a building, and adopts a lightweight six axis robotic arm mounted on a mini-gondola hoisted by a pulley system with the controlling motor located within the mini-gondola, while another set of motor located on the pulley system at the roof-top end drives the mini-gondola to traverse laterally on a set of twin-rails on the roof-top of the building. Four vacuum suction cups mounted on the minigondola through linear actuator are used to secure the mini-gondola to the wall. Each linear actuator has three ultrasonic distance sensors that measure and manage the distance between the mini-gondola and the wall to be cleaned. Once the gondola is in position, the robotic arm will be activated to start the cleaning process.

The invention claimed is: 
     
       1. A wall cleaning system for spray cleaning external walls of building, the system comprising:
 a gondola for hanging on a motor driven pulley system, wherein the motor driven pulley system comprises a pair of rails and a set of motors located at roof-top end of the pulley system; wherein the pair of rails are disposed in a horizontal plane on the roof top, and the hanging gondola is disposed in a vertical plane in parallel to an external wall; thereby, when the set of motors drives the pulley system along the pair of rails in the horizontal plane, the gondola operationally traverses in the vertical plane along the pair of rails along a linear distance of the rails for a water spraying process to be carried out; wherein the gondola comprises a controlling motor of the pulley system that hoists and lowers the gondola in parallel to the external wall of the building to be cleaned, wherein the controlling motor is located within the gondola; 
 a six-axis robotic arm, coupled with a 3D camera, and a spray nozzle on its end effector, the six-axis robotic arm is seated on the gondola for carrying out water spray cleaning on the external walls; 
 wherein the 3D camera mounted on the robotic arm operationally scans a wall area to be sprayed clean; and 
 a software program adapted for receiving the scanned results from the 3D camera and calculating the trajectory path of the spray cleaning motion for the robotic arm. 
 
     
     
       2. The system according to  claim 1 , further comprising a water weight for counter balancing on the motor-driven pulley system. 
     
     
       3. The system according to  claim 1 , further comprising a collection hood covering over the water spray nozzle to collect any water debris and paint fallouts during the spray cleaning process. 
     
     
       4. The system according to  claim 1 , wherein the gondola further comprises a pair of facade projection wheels adapted for cushioning impact of the gondola made on the facade of the wall to be cleaned. 
     
     
       5. The system according to  claim 1 , further comprises an industrial PC (personal computer) located within the gondola, the industrial PC is adapted for controlling the motor-driven pulley system to hoist and lower the gondola to locate the vertical location of the six-axis robotic arm. 
     
     
       6. The system according to  claim 5 , further comprising:
 four vacuum suction cups mounted respectively on linear actuators to secure the gondola to the wall when the robotic arm makes a stop for the cleaning process to be conducted; the suction cups are controlled by the industrial PC (personal computer) located within the gondola. 
 
     
     
       7. The system according to  claim 5 , wherein the industrial PC is adapted to control a controller located on a roof-top of the building to monitor a water level within a water container. 
     
     
       8. The system according to  claim 1 , further comprising:
 three ultrasonic distance sensors mourned on linear actuators on the gondola to measure the distance between the gondola and the wall that is to be cleaned; wherein the distance measured is fed back to control the distance between the gondola and the wall to be cleaned.